ko.computed should accept an options argument.

http://knockoutjs.com/documentation/computedObservables.html#computed_observable_reference

knockout/knockout-2.2.d.ts

@@ -62,7 +62,7 @@ interface KnockoutComputedStatic {
     fn: KnockoutComputedFunctions;
 
     (): KnockoutComputed;
-    (func: Function, context?: any): KnockoutComputed;
+    (func: Function, context?: any, options?: any): KnockoutComputed;
     (def: KnockoutComputedDefine): KnockoutComputed;
     (options?: any): KnockoutComputed;
 }